Fuel treating apparatus



Sept.. 265, 1933. P. DH. DREssLER FUEL TREATING APPARATUS 1925 '7 Sheets-Sheet l Original Filed Jun: 15

n .Q NYT Nam lnw Sept. 26, i933. P. DH. DRESSLER FUEL TREATING APPARATUS original Filed June 15, 1925' 7 Sheets-Sheet 2 Sept. 26, 1933.

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P. DH. DRESSLER FUEL TREATING APPARATUS Original Filed June 15, 1925 WEL WATER SEAL INVENTOR 7 Sheets-Sheet 5 g MEC ATTORNEY Sept 26, 1933- P. D'H. DREssLER 1,928,415

FUEL TREATING APPARATUS Original Filed June 15, 1925 7 Sheetssheet 4 Sept. 26, 1933. P. DH. DREssLl-:R

FUEL TREATING APPARATUS Original Filed June 15, 1925 7 Sheets-sheet 5 .j YN

@N NN Sept 26, 1933 P. DH. DRr-:ssLl-:R 1,928,415

FUEL TREATING APPARATUS '7 Sheets-Sheet 5 Original Filed June 15, 1925 Sept 26, 1933- P. D'H. DREssLER 1,928,415

FUEL TREATING APPARATUS Original Filed June 15, 1925 '7 Sheets-Sheet 7 TTORNEY CTL Patented Sept. 2.6, 1933 Corpcration, Pittsburgh, Pa., a corporation of .lennsylvania v originaiappiieauen Juas i5, i925,y serial No. 37,077. Divided and this vapplication May 22, i928. serai No. crasse f7 claims." (on. 20a- 417) The general object oi the present invention isv to provide improvements in the construction and arrangement of Vvkilns' or retorts for continuously subjecting material to heat treatments under predetermined kiln temperature and kiln atmosphere conditions. AMore `specifically', the object of the` invention is to provide an improved form of continuous or retort for the effective 'and economical,` treatment foi plastic blocks or briquettes `formed from an oil and Water wet mass of iinely` divided coal to give such briquettes 'the mechanical hardness and strength required to enable them to stand transportation, and in some cases to eliminate volatile smoke forming `constituents ,sof that the briquettes will burn with practically smokeless combustion. Y

The apparatuswas primarily devised and is especially adapted for use `in the manufacture of fuel from the material which is` not inappropriately called coal amalgam. Coal ramalgam is formed in a known' process of treating coal to eliminate or reduce themineral ashjiorrning constituents originally admixed withV the coal. The method of coal purification resulting in the production of coalainalgam ordinarily involves -the production of a water Wet mass ci iinely vground coal, and the intimate mixture with this mass of a suitable oiljor oil mixture having an affinity for carbon in the form of nely'ground coal, but not for the mineral ash forming constituents of the coal. This method of purifying rcoal is well adapted vfor the 'production of fuel having a satisfactory small` ash content from' a coal which like Rhode Island anthracite, contains such a large percentagey of ash :forming constituents as tov he practically incombustible in its natural state. y y

The apparatus iorrriingA the present invention is characterized in general by the` provisions made for minimizing the labor and 4attendance required in the operationoi a kiln ofpdesiraloly large capacity for drying and hardening briquettes, and if need heior eliminating smoke forming constituents therefrom, in the manner described; and comprises various novel features of construction and arrangement designed with this end. in View. The invention is further characterized by the provisions made for subjecting the briquettes to a vigorous oxidizing action at the timejwhen such action is requiredwiththe use oi a relatively small amountoi' airwhich servesv as the-oxidizing agent and by minimizing ythe' required amount oi which, l avoid the heat losses, and the dilution oi the distillatesivhich would he experienced ii more air were employed. MvThe Various ieaturesjoi novelty which characterize my invention are pointed out With par- *ticular'ity in the claims annexedto and forming ya part oi this specication; but for a better understanding of the invention, 'its advantages' and specific objects attained Ywith its use, reference should he had to the accompanying drawings and descriptive matter `in which I have illustrated and vdescribed preferred embodiments of` my invention.-

Of the drawings: f l l 'Y n Fig. l is a somewhat diagrammatic plan view oi a preferred embodiment oi `my invention;

Fig. 2 is a longitudinal section of one portion, and f v.

Fig. 2pc is a longitudinal section'oii the remainder ofthe apparatus shownlin Fig. 1;

Figs. 3 and 4 aretransverse.sections on the lines` 3--3 and fi-fi, respectively, oi Fig."2;

lig.y 5 is a transverse section on the line 5-5 Y Y to Figf2 but on a larger scale and showing only f a portion of the apparatus shown in Fig; 2;A

Fig. 'l is an enlarged section taken'similarly to Fig. 2 of the discharge end ofthe apparatus shown in Figs. l and 2; y y 1 Fig. 8 is a side elevation of a portion of the transfer apparatus shown in Figs. l' and 2;

Fig.' 9 is a sectional elevation illustratinga modiiication oi the portion oi the apparatus shown in Fig. 7;

vFig. l0 is a sectional elevation illustrating, a modified iorin'of the transfer section of the kiln;

Fig. ll is a View taken similarly*y to Fig. l0 and illustrating a secondmodication of the transfer section;

Fig. l2 is a somewhat diagrammatic plan view illustrating a modied kiln heating system;

Fig. 13 is a sectional elevation oi a heater employed in Fig. 12;

Fig.V le is an elevation of a portion of the kiln illustrating a second modification of the heating system; and Y Fig. 15 is a section on the line 15-15 of Fig. 14. In the drawings, and referring first to the form of construction shown in Figs. 1 to 7, I have shown apparatus for treating briquettes comprising two kiln chambers or kiln sections A and B, and a connecting section C through which the briquettes treated are transferred from the kiln section A to the kiln section B. The briquettes treated are carried into the kiln section A at the end of the latter remote from the section C, and are moved through the kiln section A by a belt conveyor E, and are moved through the kiln section B by a conveyor e, and are discharged from the latter onto a conveyor belt D which removes the briquettes from the apparatus with which the present invention is concerned.

The conveyor E is a belt conveyor comprising trays or pans E linked together, and track rail engaging rollers E3, and maybe of any usual or suitable construction except that the bottoms E2 of the pans E are perforated or formed of wire mesh to permit a free circulation o f the kiln atmosphere therethrough. The rollers E3 of the belt conveyor E run in one direction along upper track rails F, and run in the opposite direction along lower track rails F', and pass about suitable guide rolls E4 adjacent the transfer section C, and about guide rollsE5 at the entrance end of the kiln. The guide rolls E5 are located at some distance in front of they entrance end of the kiln section A to facilitate the loading of the briquettes onto the pans E' before the latter enter the kiln section A. As shown in Fig. 2a, the briquettes are passed onto the conveyor E directly from the extrusion machine X in which they are formed by compressing the material out of which they are formed into cylinders which are served `to form briquettes of suitablelength as they leave the extruding press. .The severed briquettes pass onto a feed belt X operated atl a suitable speed to separate the adjacent sections of each cylinder from its neighbors. At the discharge end of the feed belt X', the briquettes fall onto an inclined chute or slide X2 along which they slide onto the subjacent portion of the conveyor E.

Within the kiln section A the upper or briquette transporting portion of the conveyor E passes along and immediately above the heating iiue or combustion space by which heat is wholly or mainly supplied to the kiln section A. This space, as shown, isrdivided by a partition G into two side by side chambers or nues G which run the full length of the kiln section A and are in free communication with one another at distributed points along their lengths by means of ports G2 in the partition wall G. The top walls of the flues or chambers G are formed by plate-like bodies G4, which may advantageously be made of cast iron, except where the temperature within the combustion chamber space is high enough to make the use of more refractory material desirable, in which case the plates G4 may be made of heat resisting alloys, carborundum, or other suitable refractories. The bottom walls of the flues G are formed of refractory material and are carried by metal beams H extending transversely across the kiln structure and also supporting or assisting in supporting the walls of the combustion chambers G as a whole.

The combustion chamber structure as a whole forms a horizontal partition dividing the interior of the kiln A into an upper section A' containing the track rails F, and the upper run of the conveyor belt, and a lower compartment A2 containing the track rails F and the lower run of the conveyor E. At the entrance end of the kiln section A, the compartment A2 is shaped to provide an oil holding basin A3 through which the outgoing portion of the conveyor E passes, and into which a baille A4 extends to prevent the entrance of air into the compartment A2.

The kiln chamber B may be, and as shown is similar in general construction and arrangement to the kiln chamber A, being divided into lower and upper compartments B and B2, respectively,

'by a combustion chamber structure supported on 'transverse beams H and comprising separate longitudinal flues or combustion chambers y like the lues or chambers G rst described and having similarly formed walls. The conveyor e for moving the briquettes treated through the compartment B of the kiln section B, may be similar in general construction and in its mode of mounting to the conveyor E rst described, but the bottom walls E22 of the different tray sections of the conveyor e may be imperforate. Except as already indicated, corresponding structural parts of the two kiln sections A and B and of the conveyors E and e and their mountings are desig nated by the same reference symbols. Advantageously, each of the conveyors E and e is provided at suitable intervals along its under or inner side with transverse members E15 which form baies restricting circulation of the kiln atmosphere longitudinally through the space between the corresponding combustion chambers and the portion of the conveyor above said chambers, and which also serve as scrapers to move dust or other debris which may collect on the top walls of the combustion chambers, to the ends of the corresponding kiln chambers.

vE10 and E21 represent dust pockets arranged to receive the dust swept from the corresponding combustion chambers by the members E15 of the conveyors E and e, respectively. The dust ac cumulating in the pockets E10 and E21 may be removed from time to time through openings formed in the side wall of the kiln structure.

The transfer section C comprises provisionsfor transferring material moved through the kiln chamber A by the conveyor E, into the adjacent Yend of the conveyor e. For treating coal amalgam blocks or briquettes, it is desirable to prevent any appreciable gas flow between the kiln sections A and B through the transfer section C. As shown, the uprising buckets C1 of a vertically disposed conveyor belt C running over upper and lower pulleys C2 and C3, respectively, receives the briquettes discharged from the adjacent end of the conveyor E through a suitable chute C5. At the upper end of the conveyor C the briquettes are discharged from the buckets C4 into a chute or hopper C7 through a guide chute CG. The chute or hopper Crl may discharge directly onto the adjacent end of the upper run of the conveyor e when the conditions of operation, and in particular the atmospheric pressures in the kiln sections A and B are such that the accumulation of briquettes in the hopper C1 serves as an eiective barrier against gas ilow between the interiors of the kilns A and B. For the purpose of providing a more effective barrier against such gas flow, the hopper C7, in the construction illustrated, discharges through a bottom outlet into an intermediate hopper C8 having a bottom outlet opening into a guide chute or hopper C9 through which .the briquettes pass onto the conveyor e. The bottom discharge outlets of the hoppers CFl and C8 are controlled by bells or valves C10 and C11, respectively, which may be independently actuated yigeea-iis so that one at least of=` these valveslmayl always be closed. y The actuating provisionsfor the'valve C10 shown comprise Aa steam cylinder-C12`having its piston rod connectedthrough a lever C13 to the stem of the valve C10. The valve Cllisisimilarl'y operated by a steam cylinder-C14fandconnections including a lever C15. Thet'ransfer section Ccomprises `a` housing Wall which like the `housing walls of the kiln sectionsA `and B is rpreferably insulated toreduce heat radiation losses.

, Theprovisions `shovvnforsupplyingheat to the kiln chambers A and B comprises suitably distributed burneropenings G10 in the outer side dinary'open re tunnel kilns-,or in supplying fuel and airjfor itscombustion to ordinary mufe or combustion chamber heated kilns, and in consequence I` have thought it unnecessary to illustrate any specific r:form of` burner or re box construction for supplying burninggases to the combustion chambers y and G. Products of `comf bustion pass fromA the ends ofthe combustion sof chambers g adjacent the transfer section C, linto the adjacent" ends ofthe combustion chambersG through channels J which communicate at their endswith the chambers y andv G through ports J and J2, respectively. Y f

At the entrance end of the kiln section A products of combustion are Withdrawn from the corresponding' ends of" the combustion chambers G Vbyan exhaustgfanV K having its inlet connected tothe chambersGv through partsK and having a valved connection from its outlet to a stack K0.

In addition to the heatingmeansdescribed, provisions may be' madefor passing products of combustion Withdrawn 'from' the combustion chambers G by the fan'K'back yinto the kilncom`` partment A' to ports A5 located at some distance fromtheentrance end-.of the kiln sectio`n.`4 K3 represents a valved connection froml the outlet of* thev fanfK to the ports A5 forV this purpose. When hot 'productsiof combustion are thus introduced into the compartment A', they assist in initially heating the briquettes; and in eliminating from the latter ythe `Water originally contanedtherein.r 'a .a

In the useof theV apparatus disclosed in the preparation. of fuel in the manner previously kthe briquettes.

described, the plastic briquettes Y preferably of.

cylindrical form are piled to the proper height on the successive tray sections of the conveyor E, as those sections successively passbeneath the chute 'XZ preparatory to their reentranceinto the kilnA section A. As the fuel blocks pass through the kiln section A they are gradually heated and dried, andare subjectedfto such anaoxidizing action, that by the time they` are discharged into thechute C5 theyrare at a temperature ofjabout W- F., andare then hard and strong enough to permit of y their transportation without objectionable breakage or breeze formation.

yAs thek briquettes are thus heated up in the Acompartment A. volatile matter is driven out `of The volatile matter thus driven out of the briquettes in the initial portionv of the compartment A' is rWholly or "mainlylwate'r va,

por which may be allowed to escape to waste through suitable outlets m formed in the' roof of p the corresponding portion ofr the compartiioent.v Asfthej heatingproceeds, oil'vapors are expelled from 'thebriquettes At rstthe oil vapors excentral rovv running along the length of the kiln pellezi,` are mainly theflighter orv kmore `volatile constituentsof the oil 'mixture employedinformf ing :the kcoal amalgam,` butin the final stageof thetreatment in the kiln section A, some of the 'heavieror less volatile constituents, of the amalrf;

gam forming` oils,- and insome cases volatile confstituents of the vcoal used are expelled` The oil4 vapors' and gases driven out of the briquettes Athe transfer section C. The outlets ma and YM may be connected to condensingy apparatus for recovering and utilizing the vapors and gases escaping from the kiln through these outlets.' To accelerate the heating and oxidizing actionsas well as to minimize the amountk of atmospheric air required as anfoxidizing agent, provisions` are made for effecting an energetic circulationof the kiln atmosphere in the high temperature end of the compartment A'. The provisions shown for this purpose comprise a'circulatingA fanfN having itsrinletconnected by a collecting pipe M to the various gas outlets M, and having its outlet connected by a distributingpipe L to gas inletsL. Surrounding the pipes L,=L\, M and M is a` longitudinally extendingcasing L10 supported on thekiln top and carrying trans-'- verse supporting elements L20 and L30` for sup--y porting thepipes L and M', respectively. Y The gas outletsM are shown as arranged ina chamber, while the inlets-L are arrangedy in pairs with one inlet of each pair at each side of the cen-y tralvrow of outlets M. The individual outlets M, and the pairs of inlets L, are lalternately spaced along the length of the kiln. y Tobetter distribute the air and gas mixture` over the brisuettes, the inlets L terminate in expandingnovzzles or hoods L2,`and the inlets L at `eachside of the row of .outlets M are arranged alternately nearer to and farther away from said row as indicated in Fig. 5. Advantageously each of the inlets L and each of the outlets M, ma, and m is provided With'an individual throttling `damperor blast gate O.

As thekiln atmosphere in the high temperature end of ythe compartment A is recirculated, the air required for the production of the necessaryioxidizing effect is drawn` from the external atmosvaluable constituents ofthe vapors discharged is operated undersufl'icient vacuumv to'idravv the proper gas and vapor mixture out of the pipe MC1@ l When the condenser vacuum maintained is not` sufciently great, the vapors pass to the condens ing apparatus through thegouuet L5. The dis*- charge' tothe condenser through the outlet" M5 icov the condensing apparatus Z for recovering the when possible/is preferable, of course, because'li the vapors discharged'through` that Voutlet are less dilutedzwith air than are the vapors discharged u through the outlet L5. The vapor outlets ma from vror gas to leak out of the 'compartment A.

tothe condensing apparatus Z receiving the dis charge through the outletsM5 andr L5.

Preferably the various dampers aie so adjustr ed as to-maintain a pressure in the compartment A" approximately equal to that of the atmosphere to minimize the tendency of the air, to leak into, To minimize longitudinal circulation of the kiln'atmosphere in the portion of the compartment A above the conveyor E and the briquettes Y on the latter, the compartment A is advantageously provided `with depending roof bailles P which extend transversely across the kiln chamber and are arranged as'shown one between each gas outlet M and each adjacent pair of gas inlets L. The -lo'aflles P may each consist of a cast iron plate the upper edge of which is received in a corresponding kerf A" in the roof or top wallof the compartment A. VAdvantageously the lower edges of the baiiles P are shaped to the contour of the conveyor and the mass of briquettes stacked thereon, and are made vertically adjustable so that they may be raised and lowered to provide just sufficient clearance between the lower edges of the baiiies and the briquettes passing under them as the height to which the briquettes are piled on the conveyor E is varied. As shown, the ballesP are supported with provisions for vertical adjustments by means of hanger bolts P attached to the baies P and passing through the metallic cover or roof plate on the compartment A', and having nuts threaded on their external portions. The gases and vapors driven out of the fuel in the compartment B are withdrawn through outlets T eachy provided with a controlling damper T4 and each connected to a gas collecting main T5 which ordinarily leads to suitable apparatus such vas the condenser Z, or as shown, a separate condenser ZA for cooling the gases and vapors and recovering their valuable constituents. The cooled permanent gases having calorii'lc value, if any such are recovered, and the oil condensates recovered in the condensers Z and ZA may well be used lasv fuel in the combustion chambers y and G.

` The hardening and toughening of the briquettes obtained by'heatingfthem to a temperature of Aabout 450 F. While exposedto an oxygencontaining atmosphere, is wholly or mainly due to the oxidization of heavier or less volatile vcoinstituents of the oil in the oil amalgam and is more 'or less of'a surface action. With briquettes of ordinary size it is suicient to thus oxidize a shell portion of the briquette one-eighth of aninch 'thick or so. AThe oil oxidizing action proceeds quite rapidly after the briquettes are sufficiently heated and the briquettes are freed from the lighter more volatile amalgam *oil constituents which when present in the briquettes seem to inhibit the oxidizing action. If, as contemplated, the briquettes are loosely piled one on top of another on the pans Eto form a layer several briquettes deep, the surfaces of contact between the different briquettes do not becomeoxidized, but as the oxidizing action proceeds rapidly when the proper conditions are attained an appreciable and desirable oxidization of the surface portions not previously oxidized occurs when the original piling of the briquettes is disturbed asthe latter are discharged from the conveyor Erand are moved vbyY the conveyor C through the transfer section C. The oxidization then occurring, even though relatively small in amount, may contribute mateially to the avoidance of breeze formation in the -subsequent handling of the briquettes.

vIf the apparatus shown is operated, as it may be, to oxidize briquettes in the kiln sectionsA and C sufficiently to enable the briquettes to stand handling and transportation, the briquettes as discharged by the conveyor C form a satisfactory fuel forY many purposes. Where smokeless combustion is desired, however, the briquettes are advantageously subjected to a further treatment at a-higher temperature in the kiln section B.

When the kiln section B is utilized in eliminating volatile smoke forming constituents from the briquettes, the latter are heated in the kiln B to a temperature of something like 800 F. or higher when treating briquettes made from bituminous coals containing substantial amounts of volatileielements. Since at this temperature the fuel itself Ywill burn and the vapors expelled from the briquettes are highly iniiammable and at a temperature appreciably higher than their ignition temperature, especial care must be exercised to prevent the admission of air to the kiln section B. The introduction of air into the kiln section B from the kiln section A through the transfer section C may be prevented by provisions of the character previously described. In the form of construction shown in Figs. 1 and 2, the introduction of air into the kiln section B at the exit end of the latter is preventedby providing a quenching bath for the discharged briquettes which also serves as a means for forming a water-seal preventing the admission of air into the kiln section B. The quenching and sealing water is held in a basin S into which the lower end .of the conveyor D extends, and into which the briquettes discharged by the conveyor e slide along an inclined chute d. B represents an extension of the end wall of the kiln section B dipping down `into the quenching liquid rfar enough to form an effective water-seal, but not far enough to interfere with the passage of the briquettes along the chute d into the buckets of the conveyor D. Additional quenching means for the briquettes may be provided in theform of a spray pipe SA extending through the end wall of the kiln section B and discharging a water spray onto the briquettes as they pass along the chute d. The steam formed by the evaporation of the quenching water supplied by the pipe SA may escape from the kiln section B through the damper controlled outlet t.

It may be noted that the Rhode Island anthracite coal mentioned above is graphitic in character and contains practically no volatile matter, but the invention may be used in forming briquettes out of other materials as bituminous coal dust, or the char formed in the low temperature carbonization of coal, and in some cases some of the low volatile constituents of the carbonaceous material used in forming the briquettes will be driven out of the latter in the high temperature end of the compartment A and more will be expelled in the kiln section B.

To avoid injurious consequences from gas explosions which may occur from time to time in the Akiln sections A and B, the latter are advantageously provided with distributed openings R in the side walls which are normally closed by outwardly opening explosion doors R. To guard against injurious consequences from the ignition of the briquettes in the kiln which may occasionally occur, valved steam supply connections Q are provided by which steam or some other re rextinguishing uid may be injected nection Q is ymade to the inlet of the fan N and into the kiln at the proper point or points. Precautions against the ignition of thebriquettes andvapors driven out of the latter are especially important in the case of the high temperature end of the kiln section A because of the oxygen content and active circulation of the atmosphere therein; Forrthis reason provisions may advan-k tageously be made for injecting steam into the vcirculating'system on any predetermined rise in temperature therein. To this end a steam conis provided with an automatic valve Q2 controlled bya thermostat@3 in the pipe MC which isadjusted to open and close the valve Q2 as the temperaturerin the pipe Mfrises above and falls to or below a predetermined temperature.

35.. l into,l the kiln chamber B at its discharge end, the

It will be apparent to those skilled in the art that Various changes in the forms of constructions and modes of yuse previously describedmay be made without departing from the general principles'of my invention. `For example, a kilnasv shown in Figs. 1 and2 may be used. as previouslyr described tov complete the oxidization of the briquette oil constituents necessary to toughen and hardenfthe briquettes in the kiln sections A and 'C, While the kiln section B is used. for the elimi` fuel may be discharged through hoppers U2, U8 and U0 similargto' the 'hoppers C", C0 and C0r shown in the transfer section C and provided' with similar discharge valves or bells U10 and U11 and the apparatus sealed by al projecting part of the Wall `which they are moved through the initial oxi- Bfcontacting with the hopper U7.

While, generally speaking, itr reasons already explained, to-disturb the original placement of the briquettes on the rconveyor on dizing portion ofthe kiln to permit of some oxidation of the surfaces of the briquettes in contact in their original placement, this'result does notnecessarily require the use `of a separate con-y veyor C in thetransfer section C. Onthecontrary, as shown in Fig. 10, the dischargek end of the conveyor VE may be extended' upwardly by means of a suitably disposedguide roll E0 and j guide rails E7 so thatvthe briquettes discharged from the conveyor E will fall into a. hopper C110 having its discharge endlocated abovethezconveyor e. The sameresult can be obtained in a somewhat rsimpler manner asr shown yin Fig. 11, When conditions make it practically feasible to locate the conveyor' e at a level sufficiently below that of the conveyor E to enable the conveyor E, to discharge'into the hopper C50 without any elevation ofthe discharge end of the conveyor E. With the recirculation of the atmosphereoi the briquette drying and hardening kiln section A provided for as previously described, it is possible to supplysome orali ofthe heat requirements of the kiln section A by adding heat externally of the kilnto the air and gas mixture returnedto the kiln. Onearrangement for thus supplying some or all of the heat required in the section A is4 illustrated in Figs. 12 and, 13. To facilitate regulation of the amounts orfheat,supplied to diierent longitudinal Y' portionsof the kiln, the

'sy desirable', forv kiln atmosphere circulating provisions are con? `veniently r divided into sections longitudinallyof the kiln As shownin Figs. 12an`d 13, there are tWosuch circulating sections, MA representingl the gas off-take pipe for the high temperature end of the kiln section A, and MA2 representing the gasoi-take pipeior an intermediate portion of thezlength of the kiln section A. The orltakeV pipes MA' and MAZ are connected to thek kilnY chamber at distributed points along the length. of the ylatter by connections M which maybelVv formed and disposed generallyas shown in Figs. 5 and 6. Y Associated with the off-take pipes MA'- and MA2 are air and gas return` pipes LA'` and"` LA2 whichmay be connected to the kiln ,chambery f by connectionsL,constructed and disposed genery L.

allyasyare the connections shown in Figs. 5 and 6.k As .diagrammatically shown in Fig. l2, the'pipesY,

LA and LA2 are arranged alongside the pipes.

MA and MA2, respectively, though they may. beA locatedabove the latter, as the pipe L is shown above the pipe M in Figs. 5 and 6.

The pipe MA is connected at one end to.

the inlet of a fanNA, the outlet N10 of which `opens to an air or gas heater T. as somewhat conventionally and diagrammati-Y cally illustrated in Fig. 13 comprises a bank of tubes T10 connected at one end to a header or chamber Tl1 into which the outlet, N10 ofthe fan NA discharges. At their opposite ends theL tubes T10 are connected to a header or chamber `T12to which the corresponding end of theV pipe The latter in which any suitable fuel may be burned. As

shown, T15 represents a burner pipe forsupplying iluid fuel to the combustion chamber T14. y More or. less air may be mixed with the gases passed into the heater T to be heated therein, as iby means ofthe valved inlet` N tothe fan NA'. Excess gas is discharged from the circulating sys-k tem to'the condenser (not shown) as in` the construction first described, by means of a suitable valve outlet L5.

The pipes MA2 and LA2 are each connected through a `ian NA2 and heater T2 which may be similar, respectively, to the fan NA and heater portion of the kiln section A is heated in whole or in part by the products of combustion from the heaters T and T2 drawn from the stack outletconnections T13 thereof` by the exhaust fan NB, the outletvpipe T16` of which' is connected to the kiln inlets A5. Except as above described, the kiln'lconstruction shown in Figs. 12 and 13 may be identical with that shown in Figs. 1 and 2, in which case it is possible to supply the heat requirements of the kiln section A, wholly. by means of the heaters Tand T2,or wholly by the. use of the combustion chambers G, or partly by the use of the latter and partly by the .use of the heatersT and T2. The heaters T' and T2 are efficient and easily operated and regulated. 'Ihe division of -the kiln atmosphere circulating system into two or more sections connected tv'o diferent. longitudinal portions ofA the kiln, and

by products of combustion passing to the heater stackroutlet T13 from a combustionchamberv T14r each with its independent heater, facilitates a very., accurate control of the rate of heat supplied f to each of the corresponding longitudinal portions of the kiln.

f 'In lieu of separate fuel burning means for heating the circulating gases externally of the kiln chamber, those gases may be heated in a suitable :if external heat exchanger or exchangers in which heat. is absorbed by the circulating kiln atmosphere from any suitable or available waste heat gas source. For example, as shown in Figs. 14 and 15, the circulating gases may thus be heatnating section B of the treating kiln when the latter comprises such a section. As shown in Figs. 14 and 15, the heating gases coming from the high temperature or smoke eliminating section of the kiln through the passages `J are delivered by the latter through branches U to a pipe U which is axially disposed in the pipe LB. The latter replaces the pipe Lof Figs. 1 and 2, and

Vthe pipes LA andvLA,2 of Figs. 12 and 13. The

annular space between the pipe U and the pipe LB is connected to the kiln chamber A by regulable pipes L10, and the oir-take pipe MB of the. kiln atmosphere circulating system is connected to the kiln section A by distributed and regulable connections M10. The connections L10 and M10 may be similar in disposition and form to the connections L and M previously described except as their form is changed as the result vof the fact that the pipe MB is conveniently located above the pipe LB.

When the heat requirements of the kiln are intended to be wholly supplied by external heating provisions, the combustion chambers of the kiln A shown in Figs. l to 4 are unnecessary, and may be replaced by a simple partition A10 as shown in Fig. 15, although .even sucha partition is not always required. The elimination of the internal combustion chambers made possible by the use of means for externally'heating the circulating kiln atmosphere obviously reduces the vertical dimensions and cheapens the construction cost of the kiln structure proper.

The novel method of preparing fuel disclosed, but not claimed herein, is claimed in my prior patent 1,812,432, granted June 30, 1931, on my application, of which this application is a division.

Having now described my invention what I Aclaim as new and desire to secure by Letters' Patent is:

, l. A kiln for heat treating material comprising an elongated kiln chamber, an elongated heating ychamber dividing said kiln chamber into upper of said upper compartment.

2. A kiln having a horizontally elongated chamber divided into upper and lower compartments by an intervening hollow wall providing a combustion space extending longitudinally of the chamber, an endless belt conveyor surrounding and spaced from said hollow wall and rotatable in a vertical plane in one direction through the upper of said compartments and in the opposite direction through the lower of said compartments, and means for restricting the ow of gases longitudinally through said chamber including transversely extending roof bafes positioned at longitudinally spaced points in said upper compartment, and scraper bailes carried by said conveyor at longitudinally spaced points thereof in position to depend from the underside of the portion of the conveyor within said upper compartment.

3. A kiln for drying and hardening plastic bodies of oil wet fine coal, comprising a horizontally elongated kiln chamber, muiiie heating means arranged longitudinally in said chamber, means for continuously moving said bodies through said chamber, distributed gas inlets to and outlets from said chamber, a fan having its inlet connected to said outlets and its outlet connected to said inlets and forming a closed system for recirculating the kiln atmosphere, and means for minimizing combustion in said chamber including steam supply means and thermostatic means for regulating the supply of steam to said recirculation system in accordance with the temperature of the gases passing out of said chamber through said gas outlets.

4. A kiln for drying and hardening plastic bodies of oil Wet ne coal, comprising a horizontally elongated kiln chamber, mufle heating means therein for heating said bodies, conveying 10 means for moving said bodies through said chamber, distributed gas inlets to and outlets from one portion only of said chamber, a fan having its inlet connected to said outlets and its outlet connected to said inlets to form a closed system for recirculating the kiln atmosphere in said chamber portion, and means for adding air to and withdrawing gases from said system.

5. In a kiln for heat treating fuel, the combination with a horizontally elongated kiln chamber having a high temperature end portion and another portion in which a relatively low temperature is maintained, of muie heating means in said chamber, means for moving the fuel being treated through said chamber, means for effecting a positive circulation of the chamber atmosphere in the vhigh temperature end portion of said chamber. comprising gas inlet and outlet ports opening to said chamber end portion only, a circulating fan located externally of said chamber and having its inlet connected to said outlet ports and its outlet connected to said inlet ports, a condenser, means for passing a portion of the gases withdrawn through said outlet ports to said condenser, and conduit means connecting said condenser to a portion of said chamber in which is maintained a temperature lower than in said high temperature end portion.

6. A kiln having a horizontally elongated chamber divided into upper and lower compartments by an intervening hollow wall providing a combustion space extending longitudinally thereof, an endless belt conveyor surrounding said hollow wall and rotatable in a vertical plane longitudinally of the chamber in one direction through the upper of said compartments and in the opposite direction through the lower of said compartments, said conveyor being pervious to effect the circulation of the kiln atmosphere therethrough, and means for positively circulating the kiln atmosphere in one portion of said chamber comprising gas inlets and gas outlets arranged in the upper wall of said upper compartment and distributed alternately along a substantial portion, an intermediate transfer seetioinand a high temperature section saidfiow andhigh temperature sections extending horizonteily in opposite directions awayirom said intermediate section,

means forheating said low'end high temperature sections, a, beit conveyorr arranged to 4move materiai being treatedthrough said low temperature vvsection to said transfer `lsection, a ksecond. belt conveyor arranged to receive said inateriaifroin rsaid. transfer section and move it through said high temperature section, and conveying meeh- Y anism in seid transfer section arranged to re-r` ceive seid `material from said first mentioned conveyor `emol dispose it in a new position on seid second Y mentioned Conveyor, and gas sealing means in VAseid transfer section arranged to re# strict atmospheric flow between said 10W and high n I temperature seotionsn e t PHILIP Dy HUC DRESVSLER. 

